Rationale: Recent pediatric studies suggest a survival benefit exists for higher-volume extracorporeal membrane oxygenation (ECMO) centers.Objectives: To determine if higher annual ECMO patient volume is associated with lower case-mix-adjusted hospital mortality rate. Methods:We retrospectively analyzed an international registry of ECMO support from 1989 to 2013. Patients were separated into three age groups: neonatal (0-28 d), pediatric (29 d to ,18 yr), and adult (>18 yr). The measure of hospital ECMO volume was age group-specific and adjusted for patient-level case-mix and hospitallevel variance using multivariable hierarchical logistic regression modeling. The primary outcome was death before hospital discharge. A subgroup analysis was conducted for 2008-2013.Measurements and Main Results: From 1989 to 2013, a total of 290 centers provided ECMO support to 56,222 patients (30,909 neonates, 14,725 children, and 10,588 adults). Annual ECMO mortality rates varied widely across ECMO centers: the interquartile range was 18-50% for neonates, 25-66% for pediatrics, and 33-92% for adults. For 1989-2013, higher age group-specific ECMO volume was associated with lower odds of ECMO mortality for neonates and adults but not for pediatric cases. In 2008-2013, the volume-outcome association remained statistically significant only among adults. Patients receiving ECMO at hospitals with more than 30 adult annual ECMO cases had significantly lower odds of mortality (adjusted odds ratio, 0.61; 95% confidence interval, 0.46-0.80) compared with adults receiving ECMO at hospitals with less than six annual cases.Conclusions: In this international, case-mix-adjusted analysis, higher annual hospital ECMO volume was associated with lower mortality in 1989-2013 for neonates and adults; the association among adults persisted in 2008-2013.

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Objectives We conducted the first empirical examination of disparities in H1N1 exposure, susceptibility to H1N1 complications, and access to health care during the H1N1 influenza pandemic. Methods We conducted a nationally representative survey among a sample drawn from more than 60000 US households. We analyzed responses from 1479 adults, including significant numbers of Blacks and Hispanics. The survey asked respondents about their ability to impose social distance in response to public health recommendations, their chronic health conditions, and their access to health care. Results Risk of exposure to H1N1 was significantly related to race and ethnicity. Spanish-speaking Hispanics were at greatest risk of exposure but were less susceptible to complications from H1N1. Disparities in access to health care remained significant for Spanish-speaking Hispanics after controlling for other demographic factors. We used measures based on prevalence of chronic conditions to determine that Blacks were the most susceptible to complications from H1N1. Conclusions We found significant race/ethnicity-related disparities in potential risk from H1N1 flu. Disparities in the risks of exposure, susceptibility (particularly to severe disease), and access to health care may interact to exacerbate existing health inequalities and contribute to increased morbidity and mortality in these populations.

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Breast cancer is the second-leading cause of cancer-related deaths in women, but the details of how it begins remain elusive. Increasing evidence supports the association of aggressive triple-negative (TN) breast cancer with heightened expression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) and increased tumorinitiating cells (TICs). However, mechanistic links between EZH2 and TICs are unclear, and direct demonstration of a tumorigenic function of EZH2 in vivo is lacking. Here, we identify an unrecognized EZH2/NOTCH1 axis that controls breast TICs in TN breast carcinomas. EZH2 overexpression increases NOTCH1 expression and signaling, and inhibition of NOTCH1 activity prevents EZH2-mediated stem cell expansion in nontumorigenic breast cells. We uncover a unique role of EZH2 in activating, rather than repressing, NOTCH1 signaling through binding to the NOTCH1 promoter in TN breast cancer cells. EZH2 binding is independent of its catalytic histone H3 lysine 27 methyltransferase activity and of the Polycomb Repressive Complex 2 but corresponds instead to transcriptional activation marks. In vivo, EZH2 knockdown decreases the onset and volume of xenografts derived from TN breast TICs. Conversely, transgenic EZH2 overexpression accelerates mammary tumor initiation and increases NOTCH1 activation in mouse mammary tumor virus-neu mice. Consonant with these findings, in clinical samples, high levels of EZH2 are significantly associated with activated NOTCH1 protein and increased TICs in TN invasive carcinomas. These data reveal a functional and mechanistic link between EZH2 levels, NOTCH1 signaling activation, and TICs, and provide previously unidentified evidence that EZH2 enhances breast cancer initiation.